Sonographic determination of fetal gender.

With the advent of high resolution real-time sonographic scanning machines, fetal gender can be determined in most pregnancies of more than 25 weeks. In 72 of 112 consecutive pregnancies, fetal genitalia were well visualized and there were no errors in prediction of fetal gender. In the 40 failures, the fetal genitalia could not be detected, hence, determination was not volunteered. Follow-up showed that the failure group was equally divided between males and females, emphasizing that lack of visualization did not imply a female perineum. The reasons for failure and success, scanning techniques, and a brief review of fetal genital embryology are discussed. Caution of potential psychological effects on the parents is raised.